[SCTP]: Verify all destination ports in sctp_connectx.

We need to make sure that all destination ports are the same, since
the association really must not connect to multiple different ports
at once.  This was reported on the sctp-impl list.
Signed-off-by: NVlad Yasevich <vladislav.yasevich@hp.com>
Signed-off-by: NDavid S. Miller <davem@davemloft.net>

net/sctp/socket.c

@@ -972,6 +972,7 @@ static int __sctp_connect(struct sock* sk,
 	int walk_size = 0;
 	union sctp_addr *sa_addr;
 	void *addr_buf;
+	unsigned short port;
 
 	sp = sctp_sk(sk);
 	ep = sp->ep;
@@ -992,6 +993,7 @@ static int __sctp_connect(struct sock* sk,
 	while (walk_size < addrs_size) {
 		sa_addr = (union sctp_addr *)addr_buf;
 		af = sctp_get_af_specific(sa_addr->sa.sa_family);
+		port = ntohs(sa_addr->v4.sin_port);
 
 		/* If the address family is not supported or if this address
 		 * causes the address buffer to overflow return EINVAL.
@@ -1005,6 +1007,12 @@ static int __sctp_connect(struct sock* sk,
 		if (err)
 			goto out_free;
 
+		/* Make sure the destination port is correctly set
+		 * in all addresses.
+		 */
+		if (asoc && asoc->peer.port && asoc->peer.port != port)
+			goto out_free;
+
 		memcpy(&to, sa_addr, af->sockaddr_len);
 
 		/* Check if there already is a matching association on the